Top Letters And Comments, May 31, 2019

The Desanctification of AoA

We installed an AOA called a “Lift Reserve Indicator” in our
missionary C182. It’s purpose was exactly what the name implied…at any given
airspeed, weight, bank angle, and G load, you knew how close you were to a
stall far more precisely than indicated airspeed, sound, feel, buffet, etc. The
instructions said to completely cover the airspeed indicator during calibration
as one’s normal tendency to visually cross check an airspeed readout with the
current feel of the airplane would prevent you from ever get to the very ragged
edge of the performance envelope. Since we had wing extensions, modified
leading edge cuff, bigger engine, and a host of other standard mods for the
mission modified 182’s, without covering it up, indeed, that was the case. When
we did cover it up, and literally depended on sight picture, sound, feel, and slowly
but deliberately reaching for the very edge of the performance envelope, once
established and calibrated, this was not only a handy gizmo, but a bacon saver.

As Paul pointed out, its usefulness in a STOL contest or
when trying to stick your Super Carbon Over-The-Top VG’d, winglet,
Turbocharged, GAMI equipped, Monte Barrett, massaged TIO-540 with Top Prop,
Unicorn Cub onto a 50ft long gravel bar with a 10 knot tailwind, doing this on
purpose with scads of previous practice is a neat gizmo to physically confirm
all the tactile information.

However, when leaving a mission strip, with a cabin full of
babies, sick and/or injured, moaning/screaming people, with a sweaty,
over-worked pilot at the controls, on a hot day with some serious obstacle
negotiations required for a ‘normal’ departure, this Lift Reserve Indicator/AOA
allowed you to safely fly the airplane fully to its limits. We did not
encourage pushing every flight to its absolute limits promoting some sort of
religious aerial cowboy image. But in the course of flying in third world
countries, it made the difference between hoping your pre-flight calculations
and decisions were right vs knowing at a glance what was left of the flight
envelope.

Properly used, precisely calibrated, and properly trained in
its usage an AOA is an amazing device for improved situational awareness, not
just for competition, but when you are tired, in cockpit overload, or meeting
an emergency and knowing at a glance just what is left in the airplane can be a
lifesaver.

Otherwise it is just another set of colored LED lights added
to one’s latest gee whiz panel.

Jim Holdeman

We installed an AoA sensor in my club’s Dakota a couple
years ago in an attempt to get members feeling more comfortable landing the
plane (which can be a bit nose-heavy), more than to prevent the stall-spin
accidents we were not having. It appears to be finally having a positive effect
in getting members more comfortable with the aircraft. The only downside we
have seen is that you need a calm day to properly calibrate the sensor, so ours
currently reads a bit on the conservative side (meaning, landings are a bit
faster than necessary). Even so, I think it’s a good aid to show pilots that
it’s okay to fly final a bit slower than they’re used to, and that they can get
the same results without an instructor on board to tell them if they’re getting
a little slow because the display is fairly intuitive to interpret. I was never
under the impression that these devices would dramatically lower the stall-spin
accident, but as a tool for visually showing what relationship angle-of-attack,
load factor, and airspeed have on each other, it can be valuable if used
properly.

Gary Baluha

U.S. ADS-B Won’t Work In Canada

The article should have stated that American airplanes will
not comply with World standards. The American 978 MHZ system is not the
Worldwide 1080 MHZ system. The rest of the world is going Satellite; the U.S.
chose to go with ground-based systems.

In fact, Canadian airplanes will likely have two antennas
using the world standard frequency and should work just fine in the U.S. on the
1080 MHZ system that the U.S. uses for commercial aircraft. It is likely that
American airplanes using the 978 MHZ ground based system won’t work anywhere
except the U.S.; no Mexico or Caribbean flights either. Any Part 25 American
airplane will have the 1080 MHZ system and will work elsewhere in the world.

Brian Hope

Talking with the owner of uAvionix at SNF, he said he was
turning his small development team onto a wing top mounted system that could be
seen by the Aerion satellite network Canada will use. The issue of signal out
strength to reach the satellite network seemed to be solvable. The wing top
unit could work with ground based as well as satellite and ship to ship. FAA
has not signed off on Aerion but I bet will in time. The big advantages might
be a constant free bread crump trail on ATC radar tracking for back country,
canyon, low level remote area operations, SAR, firefighting, aerial
applicators, sheriff’s departments, medivac – think about it and you will jump
out at you. A lot of folks fly below radar/ADS-B tower coverage. I carry a PLB
but would like to have that satellite down linked bread crumb trail on ATC
computers in case I need help.

Oh, probably no bottom and roof mount antenna costs, maybe
no new expensive special transponder to deal with dual antennas. Hope uAvionix
pulls it off and the FAA buys into Aerion before I age out of flying.